| A | B |
|---|
| Apparent Brightness | measures of a star, light observed or received, or magnitude |
| Asteroids | small bodies about 1000km less in diameter in space, often found between the orbits of Mars and Jupiter |
| Atmosphere | the mixture of gasses surrounding Earth and other planets |
| Axis | straight line about which a body or geometric figure rotates |
| Orbit | curved path followed by a planet, moon or satellite |
| Astronomy | scientific study of objects outside Earth's atmosphere |
| Lunar Eclipse | event in which the shadow falls on the moon |
| Moon Phases | change in the sunlight area of one celestial body |
| Solar System | a star with groups of celestic bodies orbiting |
| Star | a celestial body made of hot gasses in which nuclear fusion occurs |
| Moon | natural satellite revolving around a planet |
| Comet | small body of ice and rock travels in elliptical orbit around the sun |
| Planet | any large natural spherical object that revolves around a star |
| Revolution | movement of an object around an other central object |
| Rotation | turning of object on its central axis |
| Seasons | periodic changes in climate due to Earth's position relative to the sun |
| Solar Eclipse | when the moon is directly between earth and sun- casting shadow on Earth |
| Solar Energy | radiant energy from the sun |
| Tide | periodic rise and fall of water level due to gravitational pull of sun and moon |
| Year | time it takes for a planet to take one revolution around a star |
